def classification(temp: float) -> str:
    if temp >= 30_000:
        return 'O'
    elif temp >= 10_000:
        return 'B'
    elif temp >= 7500:
        return 'A'
    elif temp >= 6000:
        return 'F'
    elif temp >= 5200:
        return 'G'
    elif temp >= 3700:
        return 'K'
    else:
        return 'M'